This Epic is to support shifting OVN gateway services from EDP to OCP nodes, and vice versa.

In NextGen, ovn-controller services can be hosted both on OCP workers and EDPM nodes. Gateway services may live on OCP workers and EDPM Networker nodes, specifically.

A cluster may host gateways in either of these locations. One way to e.g. end up with gateways on EDPM nodes is through adoption, that requires that existing controller nodes are taken over as EDPM Networker nodes.

Either after adoption, or otherwise during the lifetime, admins may decide to shift OVN gateway services hosted on EDPM Networker nodes to OCP workers; alternatively, they may want to scale up the service previously hosted on OCP workers into EDPM Networker nodes. Regardless of the intended path, we should make sure that this is doable.

I believe that all of the technical pieces are already lined up to make it work; so the majority of the work here would be to document and test the scenario, both after adoption and as a greenfield cluster.